"Since Q1 2007, binary version of PhysX SDK is free for commercial and non-commercial use." - sourceBetter read the license though, just in case (and I can't seem to find the actual license anywhere, so you probably need to download it to find out for sure).

OpenAL = Open source sound, if you use an earlier version. Later versions are proprietary, according to wikipedia. (Then why's it called "Open"?!)Networking = Berkley sockets, but that's rather low level. ENET maybe? RakNet is higher level but is a commercial product.

"Since Q1 2007, binary version of PhysX SDK is free for commercial and non-commercial use." - sourceBetter read the license though, just in case (and I can't seem to find the actual license anywhere, so you probably need to download it to find out for sure).

OpenAL = Open source sound, if you use an earlier version. Later versions are proprietary, according to wikipedia. (Then why's it called "Open"?!)Networking = Berkley sockets, but that's rather low level. ENET maybe? RakNet is higher level but is a commercial product.